WO1993017140A1 - Cemented carbide with binder phase enriched surface zone - Google Patents

Cemented carbide with binder phase enriched surface zone Download PDF

Info

Publication number
WO1993017140A1
WO1993017140A1 PCT/SE1993/000140 SE9300140W WO9317140A1 WO 1993017140 A1 WO1993017140 A1 WO 1993017140A1 SE 9300140 W SE9300140 W SE 9300140W WO 9317140 A1 WO9317140 A1 WO 9317140A1
Authority
WO
WIPO (PCT)
Prior art keywords
binder phase
content
cemented carbide
insert
zone
Prior art date
Application number
PCT/SE1993/000140
Other languages
French (fr)
Inventor
Åke ÖSTLUND
Ulf Oscarsson
Per Gustafson
Leif Åkesson
Original Assignee
Sandvik Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sandvik Ab filed Critical Sandvik Ab
Priority to CA002130544A priority Critical patent/CA2130544C/en
Priority to JP51474993A priority patent/JP3999261B2/en
Priority to KR1019940702730A priority patent/KR100271068B1/en
Priority to DE69334012T priority patent/DE69334012T2/en
Priority to EP93905706A priority patent/EP0627016B1/en
Priority to RU94040362/02A priority patent/RU2106932C1/en
Priority to BR9305926A priority patent/BR9305926A/en
Publication of WO1993017140A1 publication Critical patent/WO1993017140A1/en

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making non-ferrous alloys
    • C22C1/04Making non-ferrous alloys by powder metallurgy
    • C22C1/05Mixtures of metal powder with non-metallic powder
    • C22C1/051Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor
    • C22C1/057Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor with in situ formation of phases other than hard compounds by solid state reaction sintering, e.g. metal phase formed by reduction reaction
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making non-ferrous alloys
    • C22C1/04Making non-ferrous alloys by powder metallurgy
    • C22C1/05Mixtures of metal powder with non-metallic powder
    • C22C1/051Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making non-ferrous alloys
    • C22C1/04Making non-ferrous alloys by powder metallurgy
    • C22C1/05Mixtures of metal powder with non-metallic powder
    • C22C1/059Making alloys comprising less than 5% by weight of dispersed reinforcing phases
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C29/00Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
    • C22C29/02Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides
    • C22C29/06Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds
    • C22C29/08Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds based on tungsten carbide
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2998/00Supplementary information concerning processes or compositions relating to powder metallurgy
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00Aspects linked to processes or compositions used in powder metallurgy
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/26Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Definitions

  • the present invention relates to coated cemented carbide inserts with a binder phase enriched surface zone and a process for the making of the same. More par ⁇ ticularly the present invention relates to coated in ⁇ serts in which the cemented carbide has been modified so that unique technological properties have been obtained at a given chemical composition and grain size regarding the balance between very good toughness behaviour in combination with high resistance against plastic defor ⁇ mation.
  • Coated cemented carbide inserts with binder phase enriched surface zone are today used to a great extent for machining of steel and stainless materials. Thanks to the binder phase enriched surface zone an extension of the application area for the cutting tool material has been obtained.
  • Methods or processes to make cemented carbide con ⁇ taining WC, cubic phase (gamma-phase) and binder phase with binder phase enriched surface zones are within the technique referred to as gradient sintering and are known through a number patents and patent applications . According to, e.g., U.S. Patents 4,277,283 and 4,610,931 nitrogen containing additions are used and sintering ta ⁇ kes place in vacuum whereas according to U.S.
  • Patent 4,548,786 the nitrogen is added in gas phase.
  • a binder phase enriched surface zone essen- tially depleted of cubic phase is obtained.
  • U.S. Patent 4,830,930 describes a binder phase enrichment obtained through decarburization after the sintering whereby a binder phase enrichment is obtained which also contains cubic phase.
  • nitrogen gas is used in connection with the sintering in order to eliminate a process step and to improve the adhesion of a subse ⁇ quently deposited oxide coating. From fracture mechanics point of view, an enrichment of binder metal in a surface zone means that the ability • of the cemented carbide to absorb deformation and stop growing cracks increases.
  • a material is ob ⁇ tained with improved ability to withstand fracture by allowing greater deformations or by preventing cracks from growing, compared to a material with mainly the same composition but homogeneous microstruc ure.
  • the cutting material thus, obtains a tougher behaviour.
  • gradient sintering according to the known technique of vacuum sintering of nitrogen containing ce ⁇ mented carbide, the nitrogen is usually added by adding of a small amount of nitrogen containing raw materials. Due to the fact that the nitrogen activity in the fur ⁇ nace atmosphere at the sintering is below the average nitrogen activity in the cubic phase, the nitrogen con ⁇ taining cubic phase will give off nitrogen through the liquid binder phase to the furnace atmosphere.
  • a characteristic distribution of Co, Ti and W as a ' function of the distance from the surface of a cemented carbide with binder phase enrichment obtained through the above mentioned process appears, e.g., from fig 1 in U.S. 4,830,930. Outermost, there is a surface zone enriched in binder phase and completely or partly de ⁇ pleted of cubic phase. Inside this surface zone there is an area with an enrichment of the metallic element (s) present in the cubic phase, in particular Ti, Ta and Nb and where the binder phase content is considerably lower than the average content of binder phase in the interior of the cemented carbide body.
  • the decrease in binder phase content for cemented carbide with about 6 weight-% cobalt and 9 weight-% cubic phase can be up to about 2 weight-%, i.e., a relative decrease of the order of 30 %. Cracks grow easily in this zone, which has a decisive influence on the fracture frequency during machining.
  • Figure 1 shows the distribution of Co and Ti as a function of the distance from the surface of a binder phase enriched cemented carbide according to the inven ⁇ tion.
  • Figure 2 shows the distribution of Co and Ti as a function of the distance from the surface of a binder phase enriched cemented carbide according to known technique.
  • Figure 3 is a light optical micrograph in 120OX of the surface zone of a cemented carbide according to the invention in which A is surface zone enriched in binder phase and essentially free from cubic phase and B is the upper part of the zone according to the invention.
  • the present invention relates to a process performed after gradient sintering comprising sintering in vacuum or inert atmosphere of a nitrogen containing cemented carbide either as a separate process step or integrated into the gradient sintering process.
  • the process com ⁇ prises supplying nitrogen gas to the sintering furnace at a pressure of 40-400 mbar, preferably 150-350 mbar, at a temperature between 1280 and 1430°C, preferably between 1320 and 1400°C.
  • a suitable time for the nitro ⁇ gen gas treatment is 5-100 min, preferably 10-50 min.
  • the nitrogen gas is maintained until a temperature where the binder phase solidifies at about 1275-1300°C.
  • the main part of the effect is, however, achieved even if the binder phase solidifies in vacuum or in inert at ⁇ mosphere. It is particularly suitable to introduce a holding time for the nitrogen gas treatment of 5-50 min at a temperature of 1350-1380°C and a pressure of 200- 350 mbar for cemented carbides with a content of cubic phase of 6-10 weight-% expressed according to below or at 1280-1320 at a pressure of 50-150 mbar at a content of cubic phase of 8-15 weight-%.
  • the process according to the present invention is particularly intended to be applied to binder phase en- riched cemented carbide made by sintering in vacuum or inert atmosphere at very low pressure of nitrogen of ni ⁇ trogen containing material. It is effective on cemented carbide containing titanium, tantalum, niobium, tung ⁇ sten, vanadium and/or molybdenum and a binder phase ba- sed on Co and/or Ni.
  • An optimal combination of toughness and resistance against plastic deformation is obtained when the amount of cubic phase expressed as the total content of metallic elements forming cubic carbides i.e.
  • Ti, Ta, Nb etc is between 6 and 15 weight-%, preferably between 7-10 weight-% at a titanium content of 0.4-10 weight-%, preferably 1-4 weight-% for turning and 2-10 weight-% for milling and when the binder phase content is between 3.5 and 12 weight-% for turning, preferably between 5 and 7.5 weight-% and for milling, preferably between 6 and 12 weight-%.
  • the carbon content can be below carbon saturation up to a content corresponding to maximum C08, preferably C02-C08.
  • a cemented carbide with improved toughness and resis ⁇ tance against plastic deformation containing WC and cu ⁇ bic phases of carbonitride and/or carbide, preferably containing Ti in a binder phase based on Co and/or Ni with a, preferably ⁇ 50 ⁇ thick binder phase enriched surface zone is obtained.
  • binder phase enriched there is a ⁇ 300 ⁇ m, preferably ⁇ 200 ⁇ m thick zone with a binder phase content of 0.85-1, prefe ⁇ rably 0.9-1, most preferably 0.92-1 of the content in the inner portion of the cemented carbide and where the content of cubic phase is essentially constant and equal to the content in the inner portion of the cemented car ⁇ bide.
  • the binder phase enriched zone is essentially free from cubic phase i.e. it contains WC and binder phase except for the very surface where the share of cubic phase is ⁇ 50 volume-%.
  • the binder phase content in the binder phase enriched zone has within a distance from the surface of 10-30 ⁇ a maximum of >1.1, preferably 1.25-2 of the content in the inner portion of the ce ⁇ mented carbide.
  • Cemented carbide according to the invention is sui ⁇ tably coated with in itself known thin wear resistant coating with CVD- or PVD-technique.
  • a layer of carbide, nitride or carbonitride of, preferably tita ⁇ nium is applied as the innermost layer.
  • the cemented carbide Prior to the coating the cemented carbide is cleaned, e.g., by blas ⁇ ting so that possible graphite and cubic phase are es ⁇ sentially removed.
  • the present invention improves the properties of the cemented carbide.
  • no zone is obtained in the material where propagation of cracks is favourable.
  • a cemented carbide is obtained with consi ⁇ derably tougher behaviour than possible using known technique.
  • a treatment according to the in- vention was made as 30 min at 1375°C with an atmosphere of 300 mbar N2 and thereafter continued cooling in N2 down to 1200°C where a gas change to Ar was made.
  • the structure in the surface of the cutting insert consisted then of a 25 ⁇ m thick binder phase enriched zone essentially free from cubic phase and below that a zone slightly depleted of binder phase, 0.92-1 of the content in the inner portion of the insert and without essential enrichment of cubic phase, fig 1.
  • Example 2 (reference example to Example 1)
  • Example 2 From the same powder as in Example 1 inserts were pressed of the same type. These inserts were sintered according to the standard part of the sintering in Exam ⁇ ple 1, i.e., with a protective gas of Ar during the hol ⁇ ding time at 1450°C. The cooling was under a protective gas of Ar.
  • the structure in the surface consisted of a 25 ⁇ m thick binder phase enriched zone essentially free from cubic phase. Below that zone, a 100-150 ⁇ m thick zone considerably depleted of binder phase, with a minimum of about 70 % of the nominal content in the inner portion of the insert and enriched of cubic phase was found as shown fig 2.
  • the inner portion of the inserts showed C- porosity, C04. This is a typical structure for gradient sintered cemented carbide according to known technique.
  • the inserts were edgerounded and coated according to known technique.
  • Example 3 Example 3
  • Example 6 (reference example to Example 5)
  • the inserts were edgerounded and coated according Example 5.
  • Example 7 With the milling inserts from Examples 5 and 6, a milling operation in a quenched and tempered steel SS 2541 was performed as a facemilling over a workpiece 50 mm thick. The milling was performed as one tooth milling with a milling body with a diameter of 125 mm. The il- ling body was positioned such that its centre was above the exit side of the workpiece. The following cutting data were used:

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Dispersion Chemistry (AREA)
  • Powder Metallurgy (AREA)
  • Cutting Tools, Boring Holders, And Turrets (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
  • Ceramic Products (AREA)
  • Laminated Bodies (AREA)

Abstract

The present invention relates to a cemented carbide insert with improved toughness and resistance against plastic deformation containing WC and cubic phases of carbide and/or carbonitride in a binder phase based on Co and/or Ni with a binder phase enriched surface zone. The binder phase content in the insert is 3.5-12 weight-%. In a zone below the binder phase enriched surface zone the binder phase content is 0.85-1 of the content in the inner portion of the insert and the content of cubic phases essentially constant and equal to the content in the inner portion of the insert.

Description

Cemented carbide with binder phase enriched surface zone
The present invention relates to coated cemented carbide inserts with a binder phase enriched surface zone and a process for the making of the same. More par¬ ticularly the present invention relates to coated in¬ serts in which the cemented carbide has been modified so that unique technological properties have been obtained at a given chemical composition and grain size regarding the balance between very good toughness behaviour in combination with high resistance against plastic defor¬ mation.
Coated cemented carbide inserts with binder phase enriched surface zone are today used to a great extent for machining of steel and stainless materials. Thanks to the binder phase enriched surface zone an extension of the application area for the cutting tool material has been obtained. Methods or processes to make cemented carbide con¬ taining WC, cubic phase (gamma-phase) and binder phase with binder phase enriched surface zones are within the technique referred to as gradient sintering and are known through a number patents and patent applications . According to, e.g., U.S. Patents 4,277,283 and 4,610,931 nitrogen containing additions are used and sintering ta¬ kes place in vacuum whereas according to U.S. Patent 4,548,786 the nitrogen is added in gas phase. Hereby in both cases, a binder phase enriched surface zone essen- tially depleted of cubic phase is obtained. U.S. Patent 4,830,930 describes a binder phase enrichment obtained through decarburization after the sintering whereby a binder phase enrichment is obtained which also contains cubic phase. In U.S. Patent 4,649,084 nitrogen gas is used in connection with the sintering in order to eliminate a process step and to improve the adhesion of a subse¬ quently deposited oxide coating. From fracture mechanics point of view, an enrichment of binder metal in a surface zone means that the ability of the cemented carbide to absorb deformation and stop growing cracks increases. In this way, a material is ob¬ tained with improved ability to withstand fracture by allowing greater deformations or by preventing cracks from growing, compared to a material with mainly the same composition but homogeneous microstruc ure. The cutting material, thus, obtains a tougher behaviour. When gradient sintering according to the known technique of vacuum sintering of nitrogen containing ce¬ mented carbide, the nitrogen is usually added by adding of a small amount of nitrogen containing raw materials. Due to the fact that the nitrogen activity in the fur¬ nace atmosphere at the sintering is below the average nitrogen activity in the cubic phase, the nitrogen con¬ taining cubic phase will give off nitrogen through the liquid binder phase to the furnace atmosphere. There is a certain disagreement about the kinetics in this disso¬ lution process. The opinion seems to be that when the nitrogen leaves, this generates conditions for a com¬ plete dissolution of the cubic phase in the surface zone of the material. The process is thought to be controlled by diffusion of nitrogen and by diffusion of the metal components of the cubic phase. The result is that the volume which previously was occupied by the cubic phase after its dissolution is occupied by liquid binder me¬ tal. Through this process a binder phase enriched sur¬ face zone is created after the solidification of the binder phase. The metal components in the dissolved cu- bic phase diffuse inwardly and are precipitated on available undissolved cubic phase present further in the material. The content of these elements therefore increases in a zone inside the binder phase enriched surface zone at the same time as a corresponding decrease in the binder phase content is obtained.
A characteristic distribution of Co, Ti and W as a ' function of the distance from the surface of a cemented carbide with binder phase enrichment obtained through the above mentioned process appears, e.g., from fig 1 in U.S. 4,830,930. Outermost, there is a surface zone enriched in binder phase and completely or partly de¬ pleted of cubic phase. Inside this surface zone there is an area with an enrichment of the metallic element (s) present in the cubic phase, in particular Ti, Ta and Nb and where the binder phase content is considerably lower than the average content of binder phase in the interior of the cemented carbide body. The decrease in binder phase content for cemented carbide with about 6 weight-% cobalt and 9 weight-% cubic phase can be up to about 2 weight-%, i.e., a relative decrease of the order of 30 %. Cracks grow easily in this zone, which has a decisive influence on the fracture frequency during machining.
It has now turned out that if an essentially vacuum sintered nitrogen containing cemented carbide with a binder phase enriched surface zone is subjected to a nitrogen gas treatment at a temperature where the binder phase is liquid, the toughness behaviour can be increas¬ ed further. This improvement in toughness is obtained simultaneously as the resistance against plastic defor- mation remains essentially unchanged. In this way, an insert can be used in applications which today generally require two or more grades of inserts with homogeneous structure to cover the same application area.
Figure 1 shows the distribution of Co and Ti as a function of the distance from the surface of a binder phase enriched cemented carbide according to the inven¬ tion.
Figure 2 shows the distribution of Co and Ti as a function of the distance from the surface of a binder phase enriched cemented carbide according to known technique.
Figure 3 is a light optical micrograph in 120OX of the surface zone of a cemented carbide according to the invention in which A is surface zone enriched in binder phase and essentially free from cubic phase and B is the upper part of the zone according to the invention.
The present invention relates to a process performed after gradient sintering comprising sintering in vacuum or inert atmosphere of a nitrogen containing cemented carbide either as a separate process step or integrated into the gradient sintering process. The process com¬ prises supplying nitrogen gas to the sintering furnace at a pressure of 40-400 mbar, preferably 150-350 mbar, at a temperature between 1280 and 1430°C, preferably between 1320 and 1400°C. A suitable time for the nitro¬ gen gas treatment is 5-100 min, preferably 10-50 min. The nitrogen gas is maintained until a temperature where the binder phase solidifies at about 1275-1300°C. The main part of the effect is, however, achieved even if the binder phase solidifies in vacuum or in inert at¬ mosphere. It is particularly suitable to introduce a holding time for the nitrogen gas treatment of 5-50 min at a temperature of 1350-1380°C and a pressure of 200- 350 mbar for cemented carbides with a content of cubic phase of 6-10 weight-% expressed according to below or at 1280-1320 at a pressure of 50-150 mbar at a content of cubic phase of 8-15 weight-%.
The process according to the present invention is particularly intended to be applied to binder phase en- riched cemented carbide made by sintering in vacuum or inert atmosphere at very low pressure of nitrogen of ni¬ trogen containing material. It is effective on cemented carbide containing titanium, tantalum, niobium, tung¬ sten, vanadium and/or molybdenum and a binder phase ba- sed on Co and/or Ni. An optimal combination of toughness and resistance against plastic deformation is obtained when the amount of cubic phase expressed as the total content of metallic elements forming cubic carbides i.e. Ti, Ta, Nb etc is between 6 and 15 weight-%, preferably between 7-10 weight-% at a titanium content of 0.4-10 weight-%, preferably 1-4 weight-% for turning and 2-10 weight-% for milling and when the binder phase content is between 3.5 and 12 weight-% for turning, preferably between 5 and 7.5 weight-% and for milling, preferably between 6 and 12 weight-%.
The carbon content can be below carbon saturation up to a content corresponding to maximum C08, preferably C02-C08.
With the process according to the present invention a cemented carbide with improved toughness and resis¬ tance against plastic deformation containing WC and cu¬ bic phases of carbonitride and/or carbide, preferably containing Ti in a binder phase based on Co and/or Ni with a, preferably <50 μ thick binder phase enriched surface zone is obtained. Immediately inside the binder phase enriched there is a <300 μm, preferably <200 μm thick zone with a binder phase content of 0.85-1, prefe¬ rably 0.9-1, most preferably 0.92-1 of the content in the inner portion of the cemented carbide and where the content of cubic phase is essentially constant and equal to the content in the inner portion of the cemented car¬ bide. The binder phase enriched zone is essentially free from cubic phase i.e. it contains WC and binder phase except for the very surface where the share of cubic phase is <50 volume-%. The binder phase content in the binder phase enriched zone has within a distance from the surface of 10-30 μ a maximum of >1.1, preferably 1.25-2 of the content in the inner portion of the ce¬ mented carbide. Cemented carbide according to the invention is sui¬ tably coated with in itself known thin wear resistant coating with CVD- or PVD-technique. Preferably a layer of carbide, nitride or carbonitride of, preferably tita¬ nium is applied as the innermost layer. Prior to the coating the cemented carbide is cleaned, e.g., by blas¬ ting so that possible graphite and cubic phase are es¬ sentially removed.
The present invention improves the properties of the cemented carbide. When used, no zone is obtained in the material where propagation of cracks is favourable. As a consequence, a cemented carbide is obtained with consi¬ derably tougher behaviour than possible using known technique. By choosing a cemented carbide composition which has great resistance against plastic deformation, it is thus possible with the present invention to obtain the combination of very good toughness behaviour and good resistance to plastic deformation in a way that gi¬ ves a cemented carbide with unique properties .
Example 1
From a powder mixture comprising 1.9 weight-% TiC,
1.4 weight-% TiCN, 3.3 weight-% TaC, 2.2 weight-% ΝbC,
6.5 weight-% Co and rest WC with 0.15 weight% over- stoichiometric carbon content turning inserts CΝMG 120408 were pressed. The inserts were sintered with ϊ_2 up to 450°C for dewaxing, further in vacuum to 1350°C and after that with protective gas of Ar for 1 h at 1450°C. This part is completely standard sintering.
During the cooling, a treatment according to the in- vention was made as 30 min at 1375°C with an atmosphere of 300 mbar N2 and thereafter continued cooling in N2 down to 1200°C where a gas change to Ar was made.
The structure in the surface of the cutting insert consisted then of a 25 μm thick binder phase enriched zone essentially free from cubic phase and below that a zone slightly depleted of binder phase, 0.92-1 of the content in the inner portion of the insert and without essential enrichment of cubic phase, fig 1.
On the very surface of the inserts, particles of cu- bic phase were present covering about 40 % together with Co, WC and graphite. The inner portion of the inserts showed C-porosity, C04. After conventional edgerounding and cleaning, part of the cubic phase present on the surface was removed. The cutting inserts were coated by conventional CVD-technique with an 8 μm thick layer con¬ sisting of TiC and TiN.
Example 2 (reference example to Example 1)
From the same powder as in Example 1 inserts were pressed of the same type. These inserts were sintered according to the standard part of the sintering in Exam¬ ple 1, i.e., with a protective gas of Ar during the hol¬ ding time at 1450°C. The cooling was under a protective gas of Ar. The structure in the surface consisted of a 25 μm thick binder phase enriched zone essentially free from cubic phase. Below that zone, a 100-150 μm thick zone considerably depleted of binder phase, with a minimum of about 70 % of the nominal content in the inner portion of the insert and enriched of cubic phase was found as shown fig 2. The inner portion of the inserts showed C- porosity, C04. This is a typical structure for gradient sintered cemented carbide according to known technique. The inserts were edgerounded and coated according to known technique. Example 3
With the CNMG 120408 inserts from Examples 1 and 2 a test was performed as 'an interrupted turning operation in an ordinary low carbon steel. The following cutting data were used:
Speed = 80 m/min
Feed = 0.30 mm/rev
Cutting depth = 2.0 _____ Thirty edges of each insert were run until fracture. The average life for the inserts according to the inven¬ tion was 4.6 min and for the inserts according to known technique 1.3 min.
Example 4
The inserts from Examples 1 and 2 were tested in a continuous turning operation in a quenched and tempered steel with the hardness HB = 280. The following cutting data were used: Speed = 250 m/min
Feed = 0.25 mm/rev
Cutting depth = 2.0 mm
The operation led to a plastic deformation of the cutting edge which could be observed as a wear land on the clearance face of the insert. The time to obtain a land width of 0.40 mm was measured for five edges each. Inserts according to the invention obtained an average tool life of 10.9 min and according to known technique an average tool life of 11.2 min. From the Examples 3 and 4 it is evident that inserts according to the invention show a considerably better toughness behaviour than according to known technique without having significantly reduced their deformation resistance. Example 5
From a powder consisting of, in weight-%, 5.5 TiC, 1.9 TiCN, 5 TaC, 2.5 NbC, 9.5 Co and the rest WC with about 0.05% substoichiometric carbon content milling in¬ serts SPKR 1203 EDR were pressed. The inserts were sin¬ tered according to Example 1 except that the sintering temperature was 1410°C and that the treatment during the cooling was performed with the following parameters: 20 min at 1310°C at an atmosphere of 125 mbar N2.
Examination of the structure showed an about 15 μm thick binder phase enriched zone, essentially free from cubic phase, fig 3. Below this surface zone there was a thicker zone insignificantly depleted of binder phase, less than 10% below nominal content.
On the surface there were particles of cubic phase covering <10% together with WC and binder phase. The in¬ serts had no C-porosity.
After conventional edgerounding and cleaning a con- siderable portion of the cubic phase on the surface was removed particularly in the area close to the edge. The inserts were coated by conventional CVD-technique with an about 6 μm layer of TiC and TiN.
Example 6 (reference example to Example 5)
From the same powder as in Example 5, blanks were pressed of the same type and inserts were sintered ac¬ cording to the standard part of the sintering in Example 5, i.e., with a protective gas of Ar during the holding time at 1410°C. The cooling was performed under a pro¬ tective gas of Ar. The structure in the surface of the insert consisted of an about 15 μm thick binder phase enriched zone essentially free from cubic phase. Below that there was a zone 100-130 μm thick considerably depleted of binder phase, with a minimum of about 30 % below the nominal content and to the corresponding de¬ gree enriched of cubic phase. The inner portion of the inserts showed no C-porosity. This is a typical struc¬ ture for gradient sintered cemented carbide according to known technique.
The inserts were edgerounded and coated according Example 5.
Example 7 With the milling inserts from Examples 5 and 6, a milling operation in a quenched and tempered steel SS 2541 was performed as a facemilling over a workpiece 50 mm thick. The milling was performed as one tooth milling with a milling body with a diameter of 125 mm. The il- ling body was positioned such that its centre was above the exit side of the workpiece. The following cutting data were used:
Speed = 90 m/min Feed = 0.3 mm/rev Cutting depth = 2 mm
The time until insert fracture was obtained was mea¬ sured for 20 edges. The average tool life was 9.3 min for the inserts according to Example 5 and 3.2 min for Example 6. It appears that a clearly improved toughness was obtained for the inserts according to the invention.

Claims

Claims
1. Cemented carbide insert with improved toughness and resistance against plastic deformation containing WC and cubic phases of carbide and/or carbonitride in a binder phase based on Co and/or Ni with a binder phase enriched surface zone c h a r a c t e r i z e d in that the amount of cubic phase expressed as the total content of metallic elements, that forms cubic carbides, is bet¬ ween 6 and 15 weight-%, and that in a zone below the binder phase enriched surface zone the binder phase con¬ tent is 0.85-1 of the content in the inner portion of the insert and the content of cubic phases essentially constant and equal to the content in the inner portion of the insert.
2. Cemented carbide insert according to the previous claim c h a r a c t e r i z e d in that said content of cubic phases in the binder phase enriched zone is essen¬ tially = 0.
3. Cemented carbide insert according to any of the previous claims c h a r a c t e r i z e d in that the surface fraction of cubic phase on the surface of the insert is <50 %.
4. Cemented carbide insert according to any of the previous claims c h a r a c t e r i z e d in that the binder phase content in the binder phase enriched zone has a maximum >1.1 of the binder phase content in the inner portion and the said maximum is at a distance of 10-30 μm from the surface.
5. Cemented carbide insert according to any of the previous claims c h a r a c t e r i z e d in that on said insert is deposited with CVD- or PVD-technique at least one wear resistant coating.
6. Cemented carbide insert according to any of the previous claims c h a r a c t e r i z e d in that inner- most is deposited a coating of carbide, nitride or car¬ bonitride, preferably of titanium.
7. Method of making a binder phase enriched cemented carbide insert by sintering in vacuum of a nitrogen con¬ taining material in in itself known way c h a r a c t e r i z e d in that after the sintering the insert is heat treated in nitrogen at 40-400 mbar at a temperature of 1280-1430°C for a time of 5-100 min.
PCT/SE1993/000140 1992-02-21 1993-02-19 Cemented carbide with binder phase enriched surface zone WO1993017140A1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
CA002130544A CA2130544C (en) 1992-02-21 1993-02-19 Cemented carbide with binder phase enriched surface zone
JP51474993A JP3999261B2 (en) 1992-02-21 1993-02-19 Super hard alloy carbide with binder phase surface area
KR1019940702730A KR100271068B1 (en) 1992-02-21 1993-02-19 Cemented carbide with binder phase enriched surface zone
DE69334012T DE69334012T2 (en) 1992-02-21 1993-02-19 CEMENTED CARBIDE WITH BINDER PHASE OF ENRICHED SURFACE ZONE
EP93905706A EP0627016B1 (en) 1992-02-21 1993-02-19 Cemented carbide with binder phase enriched surface zone
RU94040362/02A RU2106932C1 (en) 1992-02-21 1993-02-19 Cutting plate from hard alloy and cutting plate manufacture method
BR9305926A BR9305926A (en) 1992-02-21 1993-02-19 Cemented carbide with surface area enriched with binder phase

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9200530A SE9200530D0 (en) 1992-02-21 1992-02-21 HARD METAL WITH BINDING PHASE ENRICHED SURFACE
SE9200530-5 1992-02-21

Publications (1)

Publication Number Publication Date
WO1993017140A1 true WO1993017140A1 (en) 1993-09-02

Family

ID=20385401

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1993/000140 WO1993017140A1 (en) 1992-02-21 1993-02-19 Cemented carbide with binder phase enriched surface zone

Country Status (13)

Country Link
US (2) US5549980A (en)
EP (1) EP0627016B1 (en)
JP (1) JP3999261B2 (en)
KR (1) KR100271068B1 (en)
CN (1) CN1038731C (en)
AT (1) ATE323786T1 (en)
BR (1) BR9305926A (en)
CA (1) CA2130544C (en)
DE (1) DE69334012T2 (en)
IL (1) IL104747A (en)
RU (1) RU2106932C1 (en)
SE (1) SE9200530D0 (en)
WO (1) WO1993017140A1 (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998016665A1 (en) * 1996-10-11 1998-04-23 Sandvik Ab (Publ) Method of making cemented carbide with binder phase enriched surface zone
DE19907749A1 (en) * 1999-02-23 2000-08-24 Kennametal Inc Sintered hard metal body useful as cutter insert or throwaway cutter tip has concentration gradient of stress-induced phase transformation-free face-centered cubic cobalt-nickel-iron binder
EP1043415A2 (en) * 1999-04-08 2000-10-11 Sandvik Aktiebolag Cemented carbide insert
WO2001073146A2 (en) * 2000-03-24 2001-10-04 Kennametal Inc. Cemented carbide tool and method of making
WO2002050337A1 (en) * 2000-12-19 2002-06-27 Sandvik Ab Coated cemented carbide cutting tool insert
US6638474B2 (en) 2000-03-24 2003-10-28 Kennametal Inc. method of making cemented carbide tool
EP0682580B2 (en) 1993-02-05 2005-06-01 Sandvik Aktiebolag Cemented carbide with binder phase enriched surface zone and enhanced edge toughness behaviour
EP1715082A1 (en) * 2005-04-20 2006-10-25 Sandvik Intellectual Property AB Coated cemented carbide with binder phase enriched surface zone
CN110408829A (en) * 2019-08-26 2019-11-05 广东技术师范大学 A kind of cutter and preparation method thereof that gradient laminated coating is combined with gradient hard alloy
DE112015005009B4 (en) 2014-12-24 2022-09-01 Korloy Inc. cutting tool

Families Citing this family (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE514177C2 (en) * 1995-07-14 2001-01-15 Sandvik Ab Coated cemented carbide inserts for intermittent machining in low alloy steel
EP0874919B1 (en) * 1995-11-30 2002-02-13 Sandvik Aktiebolag Coated turning insert and method of making it
SE9504304D0 (en) * 1995-11-30 1995-11-30 Sandvik Ab Coated milling insert
US5955186A (en) * 1996-10-15 1999-09-21 Kennametal Inc. Coated cutting insert with A C porosity substrate having non-stratified surface binder enrichment
EP1095168B1 (en) * 1998-07-08 2002-07-24 Widia GmbH Hard metal or ceramet body and method for producing the same
SE9802488D0 (en) 1998-07-09 1998-07-09 Sandvik Ab Coated grooving or parting insert
US6499547B2 (en) 1999-01-13 2002-12-31 Baker Hughes Incorporated Multiple grade carbide for diamond capped insert
SE516017C2 (en) 1999-02-05 2001-11-12 Sandvik Ab Cemented carbide inserts coated with durable coating
SE519828C2 (en) 1999-04-08 2003-04-15 Sandvik Ab Cut off a cemented carbide body with a binder phase enriched surface zone and a coating and method of making it
US6217992B1 (en) 1999-05-21 2001-04-17 Kennametal Pc Inc. Coated cutting insert with a C porosity substrate having non-stratified surface binder enrichment
JP3861056B2 (en) * 2000-12-19 2006-12-20 本田技研工業株式会社 Manufacturing method of cutting tool
US7169347B2 (en) * 2000-12-19 2007-01-30 Honda Giken Kogyo Kabushiki Kaisha Making a molding tool
JP2005248309A (en) * 2004-03-08 2005-09-15 Tungaloy Corp Cemented carbide and coated cemented carbide
US7699904B2 (en) * 2004-06-14 2010-04-20 University Of Utah Research Foundation Functionally graded cemented tungsten carbide
SE530850C2 (en) 2007-03-12 2008-09-30 Sandvik Intellectual Property Ways to make a ceramic insert and ceramic insert
SE0700602L (en) * 2007-03-13 2008-09-14 Sandvik Intellectual Property Carbide inserts and method of manufacturing the same
SE0701449L (en) * 2007-06-01 2008-12-02 Sandvik Intellectual Property Fine-grained cemented carbide with refined structure
US8455116B2 (en) * 2007-06-01 2013-06-04 Sandvik Intellectual Property Ab Coated cemented carbide cutting tool insert
SE0701761L (en) * 2007-06-01 2008-12-02 Sandvik Intellectual Property Fine-grained cemented carbide for turning in high-strength superalloys (HRSA) and stainless steels
WO2009111749A1 (en) * 2008-03-07 2009-09-11 University Of Utah Thermal degradation and crack resistant functionally graded cemented tungsten carbide and polycrystalline diamond
US8163232B2 (en) * 2008-10-28 2012-04-24 University Of Utah Research Foundation Method for making functionally graded cemented tungsten carbide with engineered hard surface
EP2184122A1 (en) * 2008-11-11 2010-05-12 Sandvik Intellectual Property AB Cemented carbide body and method
GB0903343D0 (en) * 2009-02-27 2009-04-22 Element Six Holding Gmbh Hard-metal body with graded microstructure
US8272816B2 (en) * 2009-05-12 2012-09-25 TDY Industries, LLC Composite cemented carbide rotary cutting tools and rotary cutting tool blanks
US8936750B2 (en) * 2009-11-19 2015-01-20 University Of Utah Research Foundation Functionally graded cemented tungsten carbide with engineered hard surface and the method for making the same
US9388482B2 (en) 2009-11-19 2016-07-12 University Of Utah Research Foundation Functionally graded cemented tungsten carbide with engineered hard surface and the method for making the same
CN101870003B (en) * 2010-06-28 2011-12-07 株洲钻石切削刀具股份有限公司 Hard alloy coated tool for milling steel and stainless steel
CN101879611B (en) * 2010-06-28 2012-01-18 株洲钻石切削刀具股份有限公司 Hard alloy coated blade for stainless steel turning
CN102672184B (en) * 2012-06-05 2015-08-12 赣县世瑞新材料有限公司 Mining nano rare earth surface peening gradient hard alloy hard alloy composite ball tooth and preparation method thereof
EP3289112B1 (en) * 2015-04-30 2021-01-06 Sandvik Intellectual Property AB Cutting tool
US11213892B2 (en) * 2016-02-29 2022-01-04 Sandvik Intellectual Property Ab Cemented carbide with alternative binder
EP3366795A1 (en) * 2017-02-28 2018-08-29 Sandvik Intellectual Property AB Cutting tool
RU2671780C1 (en) * 2017-10-30 2018-11-06 Общество с ограниченной ответственностью "Сборные конструкции инструмента, фрезы Москвитина" Working part of cutting tool
CN109881073B (en) * 2019-04-26 2020-05-22 中南大学 Alloy with surface structure of bonding metal enrichment layer and preparation method and application thereof
CN110284038B (en) * 2019-04-26 2020-07-28 中南大学 PVD coating with strong (111) texture and preparation method thereof
US11697243B2 (en) * 2019-11-14 2023-07-11 Rolls-Royce Corporation Fused filament fabrication method using filaments that include a binder configured to release a secondary material
CN111378885B (en) * 2020-03-25 2021-06-29 九江金鹭硬质合金有限公司 Hard alloy with surface layer rich in binder phase gradient structure and preparation method thereof
CN113182524B (en) * 2021-04-25 2023-06-02 赣州澳克泰工具技术有限公司 Titanium-based metal ceramic, manufacturing method thereof and cutting tool
CN114277299B (en) * 2021-12-28 2022-10-04 九江金鹭硬质合金有限公司 High-hardness hard alloy lath capable of resisting welding cracking

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4649084A (en) * 1985-05-06 1987-03-10 General Electric Company Process for adhering an oxide coating on a cobalt-enriched zone, and articles made from said process
US4828612A (en) * 1987-12-07 1989-05-09 Gte Valenite Corporation Surface modified cemented carbides
US4830930A (en) * 1987-01-05 1989-05-16 Toshiba Tungaloy Co., Ltd. Surface-refined sintered alloy body and method for making the same
US4913877A (en) * 1987-12-07 1990-04-03 Gte Valenite Corporation Surface modified cemented carbides

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5487719A (en) * 1977-12-23 1979-07-12 Sumitomo Electric Industries Super hard alloy and method of making same
US4610931A (en) * 1981-03-27 1986-09-09 Kennametal Inc. Preferentially binder enriched cemented carbide bodies and method of manufacture
US4648084A (en) * 1981-12-10 1987-03-03 Discovision Associates Storage medium track pitch detector
US4548768A (en) * 1982-08-31 1985-10-22 Aluminum Company Of America Method for the production of atomized metal particles
EP0182759B2 (en) * 1984-11-13 1993-12-15 Santrade Ltd. Cemented carbide body used preferably for rock drilling and mineral cutting
SE453202B (en) * 1986-05-12 1988-01-18 Sandvik Ab SINTER BODY FOR CUTTING PROCESSING
US4705124A (en) * 1986-08-22 1987-11-10 Minnesota Mining And Manufacturing Company Cutting element with wear resistant crown
JPH0732961B2 (en) * 1986-10-03 1995-04-12 三菱マテリアル株式会社 Surface coated tungsten carbide based cemented carbide cutting tool
US4990410A (en) * 1988-05-13 1991-02-05 Toshiba Tungaloy Co., Ltd. Coated surface refined sintered alloy
JP2762745B2 (en) * 1989-12-27 1998-06-04 住友電気工業株式会社 Coated cemented carbide and its manufacturing method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4649084A (en) * 1985-05-06 1987-03-10 General Electric Company Process for adhering an oxide coating on a cobalt-enriched zone, and articles made from said process
US4830930A (en) * 1987-01-05 1989-05-16 Toshiba Tungaloy Co., Ltd. Surface-refined sintered alloy body and method for making the same
US4828612A (en) * 1987-12-07 1989-05-09 Gte Valenite Corporation Surface modified cemented carbides
US4913877A (en) * 1987-12-07 1990-04-03 Gte Valenite Corporation Surface modified cemented carbides

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0682580B2 (en) 1993-02-05 2005-06-01 Sandvik Aktiebolag Cemented carbide with binder phase enriched surface zone and enhanced edge toughness behaviour
WO1998016665A1 (en) * 1996-10-11 1998-04-23 Sandvik Ab (Publ) Method of making cemented carbide with binder phase enriched surface zone
DE19907749A1 (en) * 1999-02-23 2000-08-24 Kennametal Inc Sintered hard metal body useful as cutter insert or throwaway cutter tip has concentration gradient of stress-induced phase transformation-free face-centered cubic cobalt-nickel-iron binder
US6655882B2 (en) 1999-02-23 2003-12-02 Kennametal Inc. Twist drill having a sintered cemented carbide body, and like tools, and use thereof
EP1043415A3 (en) * 1999-04-08 2002-08-14 Sandvik Aktiebolag Cemented carbide insert
EP1043415A2 (en) * 1999-04-08 2000-10-11 Sandvik Aktiebolag Cemented carbide insert
WO2001073146A3 (en) * 2000-03-24 2002-02-21 Kennametal Inc Cemented carbide tool and method of making
US6638474B2 (en) 2000-03-24 2003-10-28 Kennametal Inc. method of making cemented carbide tool
WO2001073146A2 (en) * 2000-03-24 2001-10-04 Kennametal Inc. Cemented carbide tool and method of making
AU2001245893B2 (en) * 2000-03-24 2005-09-29 Kennametal Inc. Cemented carbide tool and method of making
US6998173B2 (en) 2000-03-24 2006-02-14 Kennametal Inc. Cemented carbide tool and method of making
KR100835694B1 (en) * 2000-03-24 2008-06-05 케나메탈 아이엔씨. Cemented carbide tool and method of making
WO2002050337A1 (en) * 2000-12-19 2002-06-27 Sandvik Ab Coated cemented carbide cutting tool insert
US6692822B2 (en) 2000-12-19 2004-02-17 Sandvik Aktiebolag Coated cemented carbide cutting tool insert
EP1715082A1 (en) * 2005-04-20 2006-10-25 Sandvik Intellectual Property AB Coated cemented carbide with binder phase enriched surface zone
US7939013B2 (en) 2005-04-20 2011-05-10 Sandvik Intellectual Property Ab Coated cemented carbide with binder phase enriched surface zone
DE112015005009B4 (en) 2014-12-24 2022-09-01 Korloy Inc. cutting tool
CN110408829A (en) * 2019-08-26 2019-11-05 广东技术师范大学 A kind of cutter and preparation method thereof that gradient laminated coating is combined with gradient hard alloy
CN110408829B (en) * 2019-08-26 2021-07-16 广东技术师范大学 Cutter combining gradient multilayer coating with gradient hard alloy and preparation method thereof

Also Published As

Publication number Publication date
ATE323786T1 (en) 2006-05-15
CN1038731C (en) 1998-06-17
SE9200530D0 (en) 1992-02-21
CN1079179A (en) 1993-12-08
US5549980A (en) 1996-08-27
RU94040362A (en) 1996-06-27
JPH07503996A (en) 1995-04-27
IL104747A0 (en) 1993-06-10
KR100271068B1 (en) 2000-11-01
DE69334012T2 (en) 2006-11-23
CA2130544C (en) 2005-04-26
DE69334012D1 (en) 2006-05-24
JP3999261B2 (en) 2007-10-31
CA2130544A1 (en) 1993-09-02
IL104747A (en) 1996-10-31
KR950700433A (en) 1995-01-16
BR9305926A (en) 1997-08-26
US5761593A (en) 1998-06-02
EP0627016A1 (en) 1994-12-07
EP0627016B1 (en) 2006-04-19
RU2106932C1 (en) 1998-03-20

Similar Documents

Publication Publication Date Title
WO1993017140A1 (en) Cemented carbide with binder phase enriched surface zone
EP0603143B1 (en) Cemented carbide with binder phase enriched surface zone
EP0246211B1 (en) Sintered body for chip forming machining
EP0682580B1 (en) Cemented carbide with binder phase enriched surface zone and enhanced edge toughness behaviour
EP0594875B1 (en) Multilayer coated hard alloy cutting tool
US6299992B1 (en) Method of making cemented carbide with binder phase enriched surface zone
USRE35538E (en) Sintered body for chip forming machine
US5729823A (en) Cemented carbide with binder phase enriched surface zone
US20040091749A1 (en) Method of making coated cemented carbide cutting tools
EP1997938A2 (en) Coated cutting tool insert
US6468680B1 (en) Cemented carbide insert with binder phase enriched surface zone
US5576093A (en) Multilayer coated hard alloy cutting tool
EP1500713B1 (en) Method of making a fine grained cemented carbide
US7939013B2 (en) Coated cemented carbide with binder phase enriched surface zone
IL107976A (en) Cemented carbide with binder phase enriched surface zone and method for its manufacture

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): BR CA JP KR RU UA

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
WWE Wipo information: entry into national phase

Ref document number: 1993905706

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 1019940702730

Country of ref document: KR

WWE Wipo information: entry into national phase

Ref document number: 2130544

Country of ref document: CA

WWP Wipo information: published in national office

Ref document number: 1993905706

Country of ref document: EP

WWG Wipo information: grant in national office

Ref document number: 1993905706

Country of ref document: EP